Polymerizable compounds

ABSTRACT

Polymerizable compositions containing compounds based on N-acylamido-piperazines are provided. Such compounds have the formula: ##STR1## wherein: R 1 , R 2 , and R 3  are each independently selected from the group consisting of hydrogen and lower alkyl, 
     B is a linking group selected from the group consisting of carbonyl, sulfonyl, amide, and carboxyl; 
     n is one or zero; 
     R 4  is a radical selected from the group consisting of a higher aliphatic group (i.e. at least four carbon atoms, preferably from about 6 to about 50 carbon atoms), a substituted higher aliphatic group, an alicyclic group, a heterocyclic group, a non-benzenoid aromatic group, and a substituted aromatic group. Compositions containing these compounds which are stable against gelation can be prepared. The compound is preferably present in said composition in a major amount on a mole percent basis of the polymerizable monomers. These polymerizable compositions are useful as coatings, particularly in formulations containing a photoinitiator susceptible to ultra-violet radiation. The coating is exposed to ultra-violet radiation sufficient to cause the compound to polymerize and thus cure the coating.

RELATED U.S APPLICATION DATA

This application is a continuation-in-part of U.S. Ser. No. 08/242,797filed May 19, 1994, now U.S. Pat. No. 5,565,567 which is acontinuation-in-part of U.S. Ser. No. 08/073,014, Jun. 4, 1993,abandoned.

FIELD OF THE INVENTION

The present invention relates to polymerizable compounds and to theiruse. More particularly, it relates to N,N'-substituted piperazineacrylamide compounds and to processes of polymerizing these compounds,e.g. for preparing coatings.

BACKGROUND OF THE INVENTION

The use of N,N'-substituted piperazine is disclosed in a number ofdocuments. U.S. Pat. No. 5,192,766 purports to discloseN-acryloylpiperazine derivatives and their pharmaceutical use asplatelet activating factor antagonists. While the title uses the termN-acryloylpiperazine, it is clear from the disclosure that the compoundsdisclosed have a phenyl substituent bonded to the alpha,beta-unsaturatedacylamido group such that the compounds are, thus, apparently cinnamoylderivatives or homologues thereof.

M. Taningher et al., "Genotoxicity of N-acryloyl-N'-phenylpiperazine, aRedox Activator for Acrylic Resin Polymerization", Mutation Research,vol. 282, pp. 99-105 (1992) discusses the use ofN-acryloyl-N'-phenylpiperazine as a promoter of redox reactions in placeof other tertiary aromatic amines, e.g. N,N-dimethylaniline. It isspeculated that the acryloyl group will allow the compound to becopolymerized into the final material and thus avoid release thereofinto the environment.

U.S. Pat. No. 5,045,427 discloses the use of a variety of polymerizablecompounds, including N,N'-bis-acrylamido-piperazine, in a photographicmaterial. This photographic material is comprised of a support on whichis provided a light-sensitive layer comprised of a photosensitive silverhalide, a non-photo-sensitive silver salt, a reducing agent, a colorimage-forming material and a polymerizable compound.

EP-0356960 discloses polyacrylamide gels which employ as crosslinkingagents diacylyl compounds with tertiary amide groups, e.g. diacrylylpiperazine (a.k.a. N,N'-bis-acrylamido-piperazine). These gels contain achaotropic agent which permits the use of the gels in the separation ofproteins or nucleic acids.

U.S. Pat. No. 3,510,247 discloses the modification of cellulosicmaterials with tertiary bis-acrylamides, e.g. diacryloyl piperazine(a.k.a. N,N'-bis-acrylamido-piperazine). The bis-acrylamide is appliedto the cellulosic substrate and a crosslinking reaction is catalyzed bythe use of an alkaline compound and elevated temperatures, generally 200degrees F to 350 degrees F. U.S. Pat. No. 3,528,964 discloses a similarmodification, but the amides are sulfonic acid amides, wherein thesulfonic acid groups contain ethylenic unsaturation.

The technology for the production of coatings by curing monomericcompositions on the surface of various substrates is generally known.For example, J. Lowell, "Coatings", Encyclopedia of Polymer Science andEngineering, vol.3, pp. 615-675, discusses, at page 647, the productionof coatings by free-radical polymerization of monomers, e.g. unsaturatedpolyesters in a solution of an unsaturated monomer such as styrene,acrylates, and methacrylates, and polyfunctional low volatility monomerssuch as trimethylolpropane triacrylate. When such systems are cured withultra-violet radiation, a photoinitiator such as benzophenone is oftenused to increase the production of free-radicals and thereby promotecuring of the coating.

While N,N'-bis-acrylamido-piperazine is a useful monomer in manyapplications, it has been found its performance as the major componentof a radiation curable composition has certain drawbacks. For example,it has been observed that cured films thereof are quite brittle.

SUMMARY OF THE INVENTION

This invention relates to a composition of matter comprising a compoundof the formula I: ##STR2## wherein: R¹, R², and R³ are eachindependently selected from the group consisting of hydrogen and loweralkyl (preferably R¹ and R² are hydrogen and R³ is hydrogen or methyl),

B is a linking group selected from the group consisting of carbonyl,sulfonyl, amide, and carboxyl;

n is one or zero;

R⁴ is a radical selected from the group consisting of a higher aliphaticgroup (i.e. at least three carbon atoms, preferably from about 4 toabout 50 carbon atoms and more preferably about 7 to about 50 carbonatoms), a substituted higher aliphatic group, an alicyclic group, aheterocyclic group, a non-benzenoid aromatic group, and a substitutedaromatic group (said substituted aromatic group preferably having analiphatic group or a substituted aliphatic group as substituents, e.g.an alkyl group, an alkaryl group, an aralkyl group, an alkoxy group, analkaryloxy group, an aralkoxy group, an acyl group or a carboalkoxygroup (e.g. --C--(O)--O-alkyl), preferably each having at least fourcarbon atoms), wherein said composition is stable against gelation, i.e.does not gel (e.g. set to a solid mass) after an extended period oftime, e.g. at least about 150 hours, at an elevated temperature, e.g.about 60° C. It has been found that compositions which contain compoundsof the above formula may contain sufficient concentrations of residualfree amine compounds to cause the composition to gel when maintained atelevated temperatures for extended periods of time. Compositions whichhave been produced in such a way as to avoid the presence of suchconcentrations have been found to exhibit improved high temperaturestability.

A preferred class of compositions contain compounds within the scope ofthis invention having the formula II: ##STR3## wherein each R¹, R² andR³ is independently selected from the group consisting and lower alkyl,

each B and B' linking group is independently selected from the groupconsisting of carbonyl, sulfonyl, amide, and carboxyl;

n and m are independently one or zero;

R⁸ is a divalent radical selected from the group consisting of analiphatic group, an alicyclic group, an aromatic group, and aheterocyclic group (preferably a higher alkylene group (i.e. at leastfour carbon atoms, preferably from about 5 to about 50 carbon atoms), asubstituted higher alkylene group, an aryl group (preferably a phenylgroup), an aralkyl group, and an alkaryl group.

Another special class of compounds within the scope of this inventionhave the following formula III: ##STR4## wherein the variables have thesame meaning as set forth above and R¹⁷ is a polyvalent radical selectedfrom the group consisting of an aliphatic group, an alicyclic group, anaromatic group, and a heterocyclic group (preferably an alkylene group,a substituted alkylene group, an aralkyl group, a substituted aralkylgroup, an alkyleneoxyalkyl group, a substituted alkyleneoxyalkyl group,an alkyleneoxyaralkyl group, a substituted alkyleneoxyaralkyl group).

Particularly preferred compounds of this invention are those wherein nis one (and B is preferably a carbonyl group) and R⁴ is analkylene-amido group having the structure --R⁸ --C(O)--N(R⁹)--R¹⁰ or analkylene-ester group having the structure --R⁸ --C(O)--O--R¹¹, whereinR⁸ is a divalent group selected from the group consisting of a higheralkylene group, a substituted higher alkylene group, an aromatic group,and a substituted aromatic group, and R⁹, R¹⁰, and R¹¹ are independentlyselected from the group consisting of an aliphatic group, an alicyclicgroup, an aromatic group, and a heterocyclic group (preferably an alkylgroup, a substituted alkyl group, an alkenyl group, a substitutedalkenyl group, an aromatic group, and a substituted aromatic group),provided that R⁹ and R¹⁰ may together form a divalent alicyclic orheterocyclic radical, e.g. wherein R⁴ has the formula IV: ##STR5##wherein R¹² , R¹³, and R¹⁴ are independently selected from the groupconsisting of hydrogen and lower alkyl.

This invention also relates to a polymerizable composition comprising acomposition comprising a compound of formula I, above, and to a methodof coating a substrate comprising (i) contacting a surface of asubstrate with a polymerizable composition comprising a compound offormula I, above, and (ii) exposing said surface to radiation sufficientto cause said compound to polymerize in contact with said surface. Inpreferred methods, said compound is present in said composition in amajor amount on a mole percent basis of all of the monomers of saidpolymerizable composition.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to novel compositions of this invention, e.g.compositions containing compounds of formula I, and to methods of makingthese novel compositions. These compounds are piperazine derivatives inwhich one of the amine nitrogen atoms of the piperazine molecule hasbeen reacted with an acylating agent to introduce the acrylamido group(or a homologue thereof) which contains the groups R¹, R², and R³, andin which the other piperazine nitrogen atom has been reacted with acompound to introduce the R⁴ group (and optionally a B linking group)into the molecule. Thus, one of the starting materials for preparing thenovel compounds of this invention is piperazine, or a derivative thereof(e.g. an amide that is susceptible to trans-amidation).

Because piperazine has secondary amine groups, there is a possibilitythat compositions prepared therefrom will contain residual freesecondary amine, e.g. from unreacted piperazine or apiperazinyl-functional intermediate. It is believed that the presence ofeven small amounts of such impurities can lead to gelation ofcompositions which contain compounds of formula I. Such gelation isbelieved to be caused by reaction of the residual free secondary aminewith the ethylenic unsaturation of the compounds of formula I.

The composition of the invention should not gel when held at atemperature of 60° C. for an extended period of time, preferably atleast about 150 hours, more preferably at least about 175 hours, andeven more preferably at least about 200 hours. The compositions of thisinvention will typically not gel after at least 300 hours at 60° C. andmost preferably at least about 450 hours.

A means of evaluating the stability of the compositions of thisinvention with respect to gelation is to subject the composition to heataging and to measure the viscosity of the aged composition. For example,the viscosity of the composition is measured, e.g. at an ambienttemperature of 25° C. Then, the composition is aged by placing it in anoven at 60° C. After aging and cooling to an ambient temperature of 25°C., the viscosity of the composition is then measured again. If there isa significant increase in the viscosity of the composition after suchaging, the composition thus shows a tendency to gel. Preferably, thecomposition will show an increase in viscosity of less than 100%, morepreferably less than 50%, and even more preferably less than 20%, aftera period at 60° C. of at least about 3 hours, more preferably, at leastabout 24 hours and even more preferably at least about 150 hours.Ideally, the composition will show no increase in viscosity that ismeasurable within the limits of detection of the apparatus and procedurechosen after being held for more than 150 hours at 60° C. An example ofa useful viscometer is a cone and plate viscometer available as theCarri-Med CSL Rheometer, distributed by Mitech Corp., Twinsburg, Ohio,and manufactured by Carri-Med Ltd., Dorking, Surrey, UK.

Because of the presence of free secondary amine groups which is thoughtto cause gelation of compositions containing compounds of thisinvention, it is believed that methods of making the compositions ofthis invention which minimize the presence of residual free secondaryamine will be useful in preparing compositions of this invention. Suchmethods include the use of a catalyst, as discussed more fully below,for the reactions which consume the free secondary amine functionalityof the piperazine starting material and/or piperazinyl intermediate.

Also, techniques to reduce the reactivity of the mixture, such as theinclusion of polymerization inhibitors in the composition. A preferredpolymerization inhibitor in this regard is phenothiazine. Quinones, e.g.methyl hydroquinone is also useful as an inhibitor, but the mechanism ofinhibition of quinones such as methyl hydroquinone requires the presenceof oxygen for effective inhibition and it may not be practical tomaintain sufficient levels of oxygen in the compositions to allow theuse of such inhibitors.

The group R⁴ is an aliphatic, substituted aliphatic, non-benzenoidaromatic, or substituted aromatic radical having at least four carbonatoms, preferably from 4 to about 50 carbon atoms. Such aliphaticradicals include any (a) straight chain and branched alkyl radicalshaving from 4 to about 50 carbon atoms; (b) cycloalkyl radicals havingfrom 4 to about 20 carbon atoms; (c) straight chain and branched alkenylradicals having from 4 to about 40 carbon atoms; (d) cycloalkenylradicals having from 5 to about 20 carbon atoms; (e) straight chain andbranched alkynyl radicals having from 4 to about 30 carbon atoms;cycloalkynyl radicals having from 6 to about 20 carbon atoms. Aliphaticradicals also include those above-mentioned aliphatic radicals whichcontain one or more heteroatoms substituted for one or more hydrogen orcarbon atoms. The heteroatoms include the halogens, nitrogen, sulfur,oxygen, and phosphorus or groups of heteroatoms such as nitro, sulfonicacid, C₁₋₁₀ alkyl sulfonate ester, sulfoxide, sulfone, phosphoryl,trihalomethyl, and the like.

An aromatic radical is any benzenoid or non-benzenoid aromatic radicalhaving a valence of 2 to 8. A non-benzenoid aromatic radical excludessimple phenyl groups, but includes aromatic, polynuclear aromatic, othercarbocyclic aromatic radicals (e.g. those having cycloaliphatic groups),and heterocyclic aromatic radicals. For purposes of this invention, asubstituted aromatic radical is any benzenoid or non-benzenoid aromaticradical having a valence of from 2 to 6 wherein one or more hydrogenatoms is replaced by an atom or a group of atoms other than hydrogenincluding the alkyl, alkenyl, alkoxy, halogens, nitrogen, sulfur,oxygen, and phosphorus or groups of heteroatoms such as nitro, sulfonicacid, C₁₋₁₀ alkyl sulfonate ester, sulfoxide, sulfone, phosphoryl,trihalomethyl, and the like. Such an aromatic radical also includesthose radicals which contain other aliphatic moieties, aromatic groups,and/or hetero atoms.

In preferred embodiments, R⁴ has at least seven carbons and, in morepreferred embodiments, is ethylenically unsaturated. This ethylenicunsaturation should be copolymerizable with the acrylamido group definedby R¹, R², and R³, e.g. an acrylamido group. The size of the group willaffect the physical properties of a polymer prepared therefrom such thata larger R⁴ group will impart different physical properties than asmaller group. For example, a higher alkyl group as (or part of) the R⁴group will tend to impart greater flexibility to the polymer.

The B linking group, if present, is introduced into the molecule by thederivatization of one of the piperazine nitrogen atoms. The B linkinggroup is a carbonyl, sulfonyl, amide, or carboxyl group, i.e. a grouphaving the respective formula: ##STR6## In each respective case, thecompound will then have at that piperazine nitrogen atom an amidefunctionality, a sulfonamide functionality, a substituted-ureafunctionality, or a urethane functionality. Because the piperazinenitrogen atom can be covalently bonded to the R⁴ group directly, a Blinking group may not be present and, thus, n may be zero (in which casethere will be a tertiary amine functionality at that piperazine nitrogenatom).

To prepare the compounds of this invention, piperazine is reacted withtwo different derivatizing agents, the identity of each being determinedby the desired structures of R¹, R², and R³, and R⁴ (and the B linkinggroup, if present), and the leaving group (if any) in thesederivatization reactions. Thus, one of the derivatizing agents will havethe following formula VI: ##STR7## wherein R¹, R², and R³ are as definedabove and X is a leaving group (e.g. a halogen such as chlorine oranother displacable anion-forming atom or group, e.g. a carboxylategroup when the acylating agent is an acid anhydride). The other agentwill have the formula VII: ##STR8## wherein R⁴ is as defined above andX' is a leaving group (e.g. as set forth above). Of course, when thederivatizing agent is an isocyanate, i.e. that used to form asubstituted-urea functionality, there is no "leaving group" as such inthe strictest sense because the nitrogen atom of the isocyanatereactant, does not leave the molecule.

The reactions of the piperazine compound and the derivatizing agents maybe conducted sequentially or simultaneously, depending on whether thetwo acylating agents are compatible. In a simultaneous reaction, bothagents will be mixed with the piperazine compound under conditions whichwill cause the reaction to proceed as follows in scheme 1: ##STR9##wherein R¹, R², R³, R⁴, X and X' are as defined above.

If one of the derivatizing agents has a higher reactivity for piperazinethan the other derivatizing agent and this higher reactivity cannot bepracticably compensated for (e.g. by adjusting the ratio of derivatizingagents in the reaction mixture), or if the derivatizing agents willreact with each other to any degree that will provide an unacceptableby-product (e.g. if R⁸ contains a hydroxyl or amine group susceptible toacylation), then the reactions will be performed sequentially. Forexample, if R⁴ contains a hydroxyl or amine function, then a reactionsequence according to scheme 2 may be employed: ##STR10## wherein R¹⁵and R¹⁶ are hydrogen or an organic group susceptible of displacement inthe acylating reaction and the other groups are as defined above.

The reaction to introduce the acrylamide functionality into the moleculeis an acylation reaction. Acylation techniques for amide formation aregenerally described in Encyclopedia of Chemical Technology, vol. 2, pp.252-258 (Kirk-Othmer, eds., John Wiley & Sons, Inc., N.Y., N.Y., 1978),and in R. Larock, Comprehensive Organic Transformations: A Guide toFunctional Group Preparations, pp. 978 and 979 (VCH Publishers, N.Y.,N.Y., 1989) the disclosures of which are incorporated by reference. Inthe acylation of an amine, an acylating compound of the desiredmolecular formula with a leaving group is reacted with the aminecompound. For example, a carboxylic acid, acid anhydride or acid halide(e.g., chloride, of acrylic or methacrylic acid) is reacted with theamine, or derivative thereof, optionally in the presence of a catalyst,e.g. N,N-dimethylaminopyridine (typically in an amount of from about0.001% to about 5%, more typically from about 0.01% to about 2% byweight of the combined weight of the reactants). When the carboxylicacid form of the acylating agent (i.e. leaving group is a hydroxylgroup) is used, a strong acid catalyst, e.g. p-toluenesulfonic acid, istypically employed.

The reaction is typically accomplished in an inert solvent, but thecatalyst or one of the reactants may also act as a solvent. Becausepiperazine is hydrophilic, but the reaction product tends to be less so,the choice of solvent and reaction conditions can affect the efficiencyof the reaction. Generally, it has been found that an organic solventhaving a greater polarity than an aromatic solvent (e.g. toluene) ispreferred, for example, a mixture of acetonitrile and dichloromethane(e.g. 1:1 by volume) is a preferred solvent.

Because piperazine is a secondary amine, an acylating agent with a morelabile leaving group (e.g. an acid halide wherein the leaving group is ahalogen anion such as chloride) is preferred. With such a leaving group,a hydrohalic acid (e.g. hydrochloric acid) is a by-product of thereaction, and thus, an alkaline material should be added to the reactionmixture to neutralize by-product acid. It has been found that inorganicalkaline materials, e.g. alkali metal carbonates, are less preferred dueto problems associated with product isolation and that lower alkyltertiary amine bases (having the formula NR¹ R² R³ wherein R¹, R², andR³ are independently C₁ to C₄ alkyl, e.g. triethylamine) are useful inneutralizing acid formed during an acylation reaction which employs anacyl halide as the acylating agent.

It should also be noted that when an ester functional compound isprepared as a result of the use of an anhydride as an acylating agent(e.g. when phthalic anhydride is used as an acylating agent to introducethe R⁴ group into the molecule), the leaving group will be a carboxylanion that is covalently bonded to R⁸. Thus, the carboxyl group must, inthis case, be esterified to introduce the R¹¹ group into the molecule.Conventional esterification techniques which employ an alcohol havingthe formula R¹¹ --OH, or an ester thereof that is susceptible totransesterification, will be useful to esterify the carboxyl anion thatis created upon the opening of the anhydride linkage. Alternatively, thealcohol R¹¹ --OH can be reacted with an anhydride to prepare anintermediate that has both ester and carboxyl functionality. Thecarboxyl functionality of this intermediate can then be used as anacylating agent in schemes 1 and 2. If the alcohol R¹¹ --OH is a polyol,then the reaction of a molar amount of the anhydride equal to the polyolfunctionality can be used to prepare an intermediate that has sufficientcarboxyl functionality to introduce a piperazine functionality into themolecule that is equal to the polyol functionality, followed by reactionof the n-functional piperazine intermediate with a derivatizing agent offormula VI to introduce one or more ethylenic unsaturations into themolecule, i.e. as set forth in the following scheme: ##STR11## whereinR¹⁹ is the residue of an organic dicarboxylic acid anhydride.

Examples of the anhydrides that can be used as an acylating agent (orhalf-esters thereof) include substituted succinic anhydrides which arepreferred due to their low viscosity at room temperature. The lowviscosity at room temperature leads to advantages in the final product(i.e. liquid final products) as well as in the synthetic procedure (i.e.a stirrable liquid that can serve as a reactant and thus provide aliquid reaction medium without the addition of a solvent). Preferredsubstituted succinic anhydrides are the alkyl- or alkenyl-substitutedsuccinic anhydrides, e.g. n-octenyl succinic anhydride, n-nonenylsuccinic anhydride, dodecenyl succinic anhydride, and iso-octadecenylsuccinic anhydride.

The choice of the reactant X--(B)_(n) --R⁴ will determine the nature ofthe B linking group that is introduced into the molecule. When there isno B linking group, the reactant will typically be an alkyl halide or anaryl alkaline earth metal halide (e.g. the Grignard reagent phenylmagnesium bromide). Alkylation of amines is discussed in Encyclopedia ofChemical Technology, vol. 2, pp. 67 and 68 (Kirk-Othmer, eds., JohnWiley & Sons, Inc., N.Y., N.Y., 1978), the disclosure of which isincorporated by reference. When the B linking group is a carbonyl group,the reactant will typically be an acid halide and the product can becharacterized as a acylamide. Acylation reactions are discussed inEncyclopedia of Chemical Technoloay, vol. 2, pp. 252-258 (Kirk-Othmer,eds., John Wiley & Sons, Inc., N.Y., N.Y., 1978), the disclosure ofwhich is incorporated by reference. When the B linking group is asulfonyl group, the reactant will typically be a sulfonyl halide and theproduct can be characterized as a sulfonamide. The reaction to form asulfonamide is very similar to an acylation reaction. The synthesis ofsulfonamides is discussed in Encyclopedia of Chemical Technology, vol.2, pp. 795 and 803-806 (Kirk-Othmer, eds., John Wiley & Sons, Inc.,N.Y., N.Y., 1978), the disclosure of which is incorporated by reference.

As discussed above, when the B linking group is an amide, the reactantwill typically be an isocyanate. The synthesis of urea compounds by thereaction of an amine with an isocyanate is discussed in Encyclopedia ofChemical Technology, vol. 12, pp. 319-321 (Kirk-Othmer, eds., John Wiley& Sons, Inc., N.Y., N.Y., 1980), the disclosure of which is incorporatedby reference.

Further, when the B linking group is a carboxylate group such that thecompound has a urethane functionality, a reaction sequence as shown inscheme 3, below will be useful: ##STR12## wherein all of the variablesare as set forth above and R¹⁸ is a group susceptible totransesterification, e.g. an alkoxy group or an aryloxy group,preferably lower alkoxy (e.g. a methoxy group). Transesterificationreactions are generally known. They are typically catalyzed by a base(e.g. alkali) or an acid and are governed by principles of mass transferso that the reaction can be driven to substantial completion by removalof the by-product alcohol R¹⁸ --OH (e.g. by distillation).Transesterification reactions are discussed in Encyclopedia of ChemicalTechnology, vol. 9, pp. 306-308 (Kirk-Othmer, eds., John Wiley & Sons,Inc., N.Y., N.Y., 1980), the disclosure of which is incorporated byreference.

In the special case where R⁴ has the formula IV, i.e. there are twopiperazine groups in the molecule, it is convenient to employ thefollowing scheme 4 to prepare the compound: ##STR13## wherein the groupsare selected as set forth above. It should be noted that the R¹, R², andR³ groups on each end of the molecule need not be the same, i.e. if, forexample, a mixture of acryloyl chloride and methacryloyl chloride areused to acylate the di-piperazine intermediate in scheme 4 above, theR¹, R², and R³ groups on one end of the molecule will differ from theR¹, R², and R³ groups on the other end of the molecule. The R⁸ group isderived from a di-carboxylic acid compound, preferably a di-carboxylicacid having a higher alkylene group between the acid groups, or areactive derivataive thereof, e.g. an anhydride, an acid halide, ortransesterifiable ester thereof. Examples of diacids include aliphaticdiacids, e.g. succinic acid and substituted succinic acids (as describedbelow, and aromatic diacids, e.g. phthalic acid. Preferred diacidshaving a higher alkylene chain are described in Encyclopedia of PolymerScience and Technology, vol. 11, pp. 476-489, (John Wiley & Sons, Inc.N.Y., N.Y., 1988), the disclosure of which is incorporated herein byreference. Such preferred diacids include dimer acids (produced by thedimerization of fatty acids that results in an R⁸ group which is adivalent hydrocarbon, e.g. oleic acid that results in an R⁸ group whichis a divalent hydrocarbon having 36 carbon atoms), tridecanedioc acid(produced by the ozonolysis of erucic acid), C₁₉ diacid (produced by thehydroformylation of oleic acid with carbon monoxide) and C₂₁ diacid(produced by the reaction of tall oil fatty acid with acrylic acid). Thepreferred diacids are dimer acids. Dimer acids are also described indetail in U.S. Pat. No. 5,138,027 (Van Beek), the disclosure of which isincorporated herein by reference. The compounds of formula II can beconsidered compounds of formula I wherein R⁴ is a substituted aliphaticgroup, e.g. when R⁸ is derived from a dimer acid such that R⁴ is ahigher alkyl group substituted with an acrylamido-piperazinyl-carbonylgroup.

In the special case of compounds of formula III, i.e. there are twopiperazine groups in the molecule and an R¹⁷ group, it is convenient toemploy the following scheme 5 to prepare the N,N'-diacylamido-piperazinecompound: ##STR14## wherein the groups are selected as set forth above.It should be noted that the R¹, R², and R³ groups on each end of themolecule need not be the same; if, for example a mixture of acryloylchloride and methacryloyl chloride are used to acylate the di-piperazineintermediate in scheme 5 above, the R¹, R², and R³ groups on one end ofthe molecule will differ from the R¹, R², and R³ groups on the other endof the molecule. The reactant HO--R¹⁷ --OH is a polyol reactant.Examples of polyols are polyalkyleneoxy compounds, e.g. those describedin Encyclopedia of Polymer Science and Technology, vol. 6, pp. 225-322(John Wiley & Sons, Inc., N.Y., N.Y. 1986), the disclosure of which isincorporated herein by reference. Preferred polyols are alkyleneoxyalkylor alkyleneoxyaralkyl compounds having at least two free hydroxylgroups. Examples of alkyleneoxyalkyl compounds are ethoxylated and/orpropoxylated lower alkane polyols, e.g. propoxylated trimethylolpropane(e.g. Photonol PHO-7072), ethoxylated trimethylolpropane (e.g. PhotonolPHO-7149, Photonol PHO-7155, and Photonol PHO-7158), propoxylatedglycerol (e.g. Photonol PHO-7094), propoxylated neopentylglycol (e.g.Photonol PHO-7127), and ethoxylated neopentylglycol (e.g. PhotonolPHO-7160). Examples of alkyleneoxyaralkyl compounds are ethoxylatedand/or propoxylated alkylpolyphenols, e.g. propoxylated bisphenol A(e.g. Photonol PHO-7020) and ethoxylated bisphenol A (e.g. PhotonolPHO-7025, and Photonol PHO-7028). All of these Photonol products areavailable commercially from Henkel Corporation, Ambler, Pa.

The polymerizable components useful in this invention are any materialswhich are capable of addition copolymerization with theN,N'-diacylamido-piperazine compounds of formula I described above toform a useful polymer composition. The polymerization of acrylamidemonomers is discussed in Encyclopedia of Polymer Science andEngineering, vol. 1, pp. 169-211 (John Wiley & Sons, Inc., N.Y., N.Y.,1985), the disclosure of which is incorporated by reference. Thepolymerizable components include mono-ethylenically unsaturated monomerscapable of homopolymerization, or copolymerization with otherethylenically unsaturated monomers, as well as copolymerization with thecompound. Examples of suitable mono-ethylenically unsaturated compoundsinclude alkyl acrylates, alkyl methacrylates, vinyl esters, vinyl aminesand vinyl aromatic compounds. Specific examples include ethyl acrylate,t-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, laurylmethacrylate, vinyl acetate, N-vinyl pyrrolidinone, styrene, and vinyltoluene.

Polymerizable compounds which may be used in the present invention areaddition-polymerizable monomers and oligomers and polymers thereof.Addition-polymerizable monomers are compounds having one or morecarbon-carbon unsaturated bonds. Examples of the compounds are acrylicacid and salts thereof, acrylates (e.g. lower alkyl acrylates),acrylamides (e.g. lower N-alkyl acrylamides), methacrylic acid and saltsthereof, methacrylates, methacrylamides, maleic anhydride, maleates,itaconates, styrenes, vinyl ethers, vinyl esters, N-vinyl-heterocycliccompounds, allyl ethers, and allyl esters and derivatives thereof.

In addition, a crosslinking compound having an activity of increasingthe degree of hardening or the viscosity of the formed polymericcompounds, by crosslinking the polymeric coating, can be employed. Suchcrosslinking compounds are so-called poly-functional monomers having aplurality of ethylenic or vinyl groups or vinylidene groups in themolecule. This addition will be especially useful if theN,N'-substituted acylamido-piperazine compound chosen has only oneethylenic unsaturation, e.g. N-(o-alkyl-phthalamido),N'-acrylamido-piperazine.

Examples of a number of the various polymerizable compounds which may beincluded in the polymerizable compositions of the present inventioninclude acrylic acid, methacrylic acid, butyl acrylate, methoxyethylacrylate, butyl methacrylate, acrylamide, N, N-dimethylacrylamide, N,N-diethylacrylamide, N-acrylamido-morpholine, N-acrylamido-piperidine,glycidyl acrylate, 2-ethylhexyl acrylate, acrylic acid anilide,methacrylic acid anilide, styrene, vinyltoluene, chlorostyrene,methoxystyrene, chloromethylstyrene, 1-vinyl-2-methylimidazole,1-vinyl-2-undecylimidazole, 1-vinyl-2-undecylimidazoline,N-vinylpyrrolidone, N-vinylcarbazole, vinylbenzyl ether, vinylphenylether, methylene-bis-acrylamide, trimethylene-bis-acrylamide,hexamethylene-bis-acrylamide, N, N'-diacrylamidopiperazine,m-phenylene-bis-acrylamide, p-phenylene-bis-acrylamide, ethylene glycoldiacrylate, propylene glycol dimethacrylate, diethylene glycoldiacrylate, polyethylene glycol diacrylate,bis(4-acryloxypolyethoxyphenyl)propane, 1,5-pentanediol diacrylate,neopentyl glycol diacrylate, 1,6-hexanediol acrylate, polypropyleneglycol diacrylate, pentaerythritol triacrylate, trimethylolpropanetriacrylate, pentaerythritol tetraacrylate, N-methylol-acrylamide,diacetone-acrylamide, triethylene glycol dimethacrylate, pentaerythritoltetra-allyl ether.

Examples of useful reactive oligomers include low molecular weightpolymers (e.g., about 1,000 to 25,000 g/mole) having polymerizableethylenic unsaturation. Specific examples include maleic-fumaricunsaturated polyesters, acrylate-terminated polyesters (e.g. thosedescribed in U.S. Pat. No. Re 29,131 to Smith et al.) acrylic copolymershaving pendant vinyl unsaturation (e.g. allyl acrylate/acryliccopolymers), epoxy acrylates, and polyurethane acrylates.

Examples of useful reactive polymers include graft polymerizablepolyolefins, e.g., polyethylene, polypropylene, and ethylene/propylenecopolymers, and polymers having polymerizable ethylenic unsaturationalong the backbone, for example diene homopolymers or copolymers (e.g.,styrene-butadiene copolymers, cis-polybutadiene, andbutadiene-acrylonitrile copolymers).

The polymerizable component and N,N'-acylamido-piperazine compound canbe mixed in any convenient manner which will place the component andcompound in a sufficiently reactive association to form a polymer onsubsequent curing thereof. Generally, simple mixing of the polymerizablecomponent and N,N'-acylamido-piperazine compound will suffice. Otheruseful techniques include conventional wet chemistry techniques, e.g.,dissolution in a common solvent system.

The amount of the N,N'-acylamido-piperazine compound in thepolymerizable composition will vary depending upon the contemplatedapplication of the cured polymeric composition, but will generally besufficient to detectably affect the properties of the polymer and/orcrosslink the polymeric composition. The affect on the properties of thepolymer and/or degree of crosslinking of the cured polymeric compositioncan be determined by conventional techniques, e.g., adhesion tosubstrates, resistance to solvents (e.g., swelling, extractibles, and/orspot-testing). In preferred compositions, the amount of adiacrylamido-piperazine compound will be sufficient to measurablyincrease the gel content of the cured polymeric composition, e.g.,preferably by at least about 1% and more preferably at least about 5%.Typical levels of N,N'-acylamido-piperazine compound that have only oneethylenic unsaturation will range from about 5 mole % to about 90 mole%, preferably from about 10 mole % to about 50 mole %, of thepolymerizable components of the polymerizable composition.

The polymerizable composition of the present invention can be applied toa variety of substrates. These include, for example, porous stock suchas paper and cardboard, wood and wood products, metals such as aluminum,copper, steel, and plastics such as P.V.C., polycarbonates, acrylic andthe like. After addition of a suitable photoinitiator, e.g., PHOTOMER51® brand photoinitiator (benzyl dimethyl ketal), the compositions areapplied by methods such as spraying, rollcoating, flexo and gravureprocesses onto a selected substrate. The resulting coated substrate,e.g., a paper, is typically cured under a UV or electron beam radiation.The compositions may optionally include other substances such aspigments, resins, monomers and additives such as anti-oxidants andrheological modifiers. For example, flow and levelling agents, e.g.BYK-307 and/or BYK 310, available form BYK-Chemie USA, Wallingford,Conn., can be used to modify the coating characteristics of thepolymerizable composition. Methods of coating and materials used incoatings are described in Encyclopedia of Polymer Science andEngineering, vol. 3, pp. 552-671 and supp. vol., pp. 53, 109 and 110(John Wiley & Sons, Inc., N.Y., N.Y., 1985), the disclosure of which isincorporated by reference.

The coated surface is then exposed to sufficient energy, e.g. heat orelectromagnetic radiation to cure the composition through the reactivepi bonds. Suitable sources of radiation include ultraviolet light,electron beam or radioactive sources such as are described in U.S. Pat.No. 3,935,330 issued Jan. 27, 1976 to Smith et al. To enhance the rateof curing free radical initiators may be included in the compositionsuch as benzoin, benzoin ethers, Michier's Ketone and chlorinatedpolyaromatic hydrocarbons. Other free radical initiators are ordinarilyorganic peroxides, hydroperoxides, peroxy acids, peroxy esters, azocompounds, ditertiary butyl peroxide, benzoyl peroxide,2,4-dichlorobenzoyl peroxide, tertiary butyl hydroperoxide,1,5-dimethyl-2,5-bis (hydroperoxy)-hexane, peroxyacetic acid,peroxybenzoic acid, tertiary butyl peroxypivalate, tertiary butylperoxyacetic acid and azobisisobutyronitrile. The free radical initiatoris typically present at from about 0.01 to about 20% by weight of theradiation curable components. To ensure that the composition does notprematurely polymerize, a free radical inhibitor may be added to thepolymerizable composition. Examples of suitable inhibitors includehydroquinone and the methyl ether thereof or butylated hydroxy tolueneat a level of from about 5 ppm to about 2000 ppm by weight of thepolymerizable components.

Particularly preferred sources of radiation emit electromagneticradiation predominantly in the ultra-violet band. When such a source isused, the polymerizable composition preferably contains a photoinitiatorsusceptible to ultra-violet radiation, e.g. benzoin, benzoin ethers,alpha, alpha-dimethoxy-alpha-phenylacetophenone, diethoxyacetophenone,alpha-hydroxy-alpha,alpha-dimethylacetophenone, and1-benzoylcyclohexanol.

The amount of radiation necessary to cure the composition will of coursedepend on the angle of exposure to the radiation, the thickness of thecoating to be applied, and the amount of polymerizable groups in thecoating composition, as well as the presence or absence of a freeradical initiating catalyst. For any given composition, experimentationto determine the amount of radiation sensitive pi bonds not curedfollowing exposure to the radiation source is the best method ofdetermining the amount and duration of the radiation required.Typically, an ultra-violet source with a wavelength between 200 and 300nm (e.g. a filtered mercury arc lamp) is directed at coated surfacescarried on a conveyor system which provides a rate of passage past theultra-violet source appropriate for the radiation absorption profile ofthe composition (which profile is influenced by the degree of curedesired, the thickness of the coating to be cured, and the rate ofpolymerization of the composition).

The polymerizable compositions of this invention may also find use as astarting material for applications in addition to coatings. Particularexamples include articles formed by the shaping (e.g. casting, molding,or extrusion) of polymeric materials, as well as binders (e.g. forpigments of printing inks, magnetic media, etc.), or by use of thecomposition as an adhesive or sealant. Further, steric polymerizationtechniques as described by E.J. Murphy et al., "Some Characteristics ofSteric Polymerization", Proceedings of RadTech 1990--North America, vol.I, pp. 217-226, the disclosure of which is incorporated herein byreference, may be useful. In such techniques, where a pool ofpolymerizable composition is subjected to a focused laser beam ofultra-violet radiation, an object is formed within the pool fromdiscrete thin layers formed at the top of the pool where the laser beamis focused. In a sense, the composition polymerizes in contact with thesurface of a layer of cured polymer. The particular procedures used andthe choice of the other necessary or desirable starting materials,catalysts, and other functional additives, as well as the amount ofN,N'-acylamido-piperazine compound, will be within the skill of the artwithin which the crosslinked polymeric composition is employed.

U.S. Ser. No. 08/242,797, filed May 19, 1994, U.S. Pat. No. 5.565.567which is a continuation-in-part of U.S. Ser. No. 08/073,014, filed Jun.4, 1993, now abandoned, the disclosures of which are incorporated hereinby reference, discloses acrylamido-piperazine compounds useful inradiation curable coatings.

The following examples will serve to further illustrate the invention,but should not be construed to limit the invention, unless expressly setforth in the appended claims. All parts, percentages, and ratios are byweight unless otherwise indicated in context.

EXAMPLES

Coating Procedures and Apparatus

In the following examples, coatings were prepared by the followingprocedure. The substrates used, unless noted otherwise, were aluminumpanels available commercially as Q-panels from Q-Panel Corporation, andare coated using RDS Coating Rods. The curing apparatus was a FusionsSystems Model F440 with a 300 watt/inch mercury bulb. The variables inthe tests include the speed of the belt which transports the substrateunder the bulb, the number of passes the substrate makes under the bulb,and the thickness of the coating on the substrate, and variations in thecoating formulation, e.g. type and amount of additives and co-monomers,which will be noted below.

Example 1

The compound N-acrylamido-N'-(n-butyl phthalamido)-piperazine wasprepared using the specific procedure set forth therebelow. The compoundwas then used to form a coating by the procedure set forth below.

Procedure for the Synthesis of Phthalic Piperazine Amide Acid

Into a 3 liter, four-necked round-bottom flask fitted with mechanicalstirring, dry nitrogen and a reflux condenser were charged 129.2 gramspiperazine, 750 ml dichloromethane, 750 ml acetonitrile, and 6.1 gramsdimethylaminopyridine. To this mixture was added portion-wise 222.2 gphthalic anhydride. Following the addition, the mixture was refluxed for3 hours, at the end of which period no residual anhydride was present byinfrared analysis. The solvent was decanted from the solid productprecipitate.

Procedure for the Synthesis of Phthalic Piperazine Amide Acid ButylEster

To the precipitated product from the previous procedure were added 150ml 12N HCl, 200 ml n-butanol, and 7.1 g p-toluenesulfonic Acid. ADean-Stark trap was attached to the reflux condenser, and the reactionmixture was heated to reflux. The mixture was refluxed for 15 hours, atwhich time infrared analysis showed extensive conversion to the butylester, and TLC showed a single product using 1:1 methanol-water aseluent. The ester product was separated from the residual n-butanol bypressure filtration.

Procedure for the Synthesis of Phthalic Piperazine Acrylamide ButylEster

Into a 3 liter, four-necked round-bottom flask fitted with a refluxcondenser dry air, and mechanical stirring, were charged 324 g of theester from the previous procedure, 500 ml acetonitrile, 250 mldichloromethane, 253 g triethylamine, 3.0 g dimethylaminopyridine, and0.21 g hydroquinone monomethyl ether. The mixture was cooled in an icebath, and 100 g acryloyl chloride was added dropwise over a period oftwo and one half hours, with the addition rate sufficient to maintain areaction temperature of 0-10 degrees C. The mixture was then allowed towarm to ambient temperature and stirred for an additional 90 minutes.The reaction mixture was then filtered through a Buchner funnel toremove undissolved solids. The resultant solution was washed with 1N HClto remove unreacted triethylamine, dried with anhydrous sodium sulfate,and stripped of solvent under reduced pressure.

Procedure for Coating with Phthalic Piperazine Acrylamide Butyl Ester

A coating formulation was prepared by mixing 93 parts by weight of theneat phthalic piperazine acrylamide butyl ester, and 7 parts by weightof a photoinitiator blend consisting of 4 parts by weight of Darocure1173, a photoinitiator available from Ciba-Geigy, Hawthorne, N.Y., 2parts by weight of Photomer 81, a liquid form of benzophenone availablefrom Henkel Corporation, Ambler, Pa., and 1 part by weight oftriethanolamine. This composition was coated at 6.86 micrometersthickness and cured in one pass at 100 ft./min. The resulting coatingexhibited a pencil hardness of 2H and dissolved with two methyl ethylketone (MEK) rubs. The resistance to MEK could be improved by theinclusion of a di-ethylenically unsaturated monomer, e.g.N,N'-bis-acrylamido piperazine.

Example 2

The compound bis-(N'-acrylamido-piperazinyl) dimer acid amide wasprepared using the specific procedures set forth therebelow. Thecompound was then used to form a coating by the procedure set forthbelow.

Procedure for the Synthesis of EMPOL 1008 Acid Chloride

Into a 1 liter, four-necked round-bottom flask fitted with a magneticstirrer, reflux condenser, thermometer, and dry nitrogen were charged250.0 grams of EMPOL 1008, 250 ml hexane, and 2 ml dimethylformamide. Tothe stirred mixture was added 115.7 g thionyl chloride dropwise throughan addition funnel over a period of 30 minutes. No exotherm was noted,however significant bubbling was noted. Infrared spectroscopic analysisof the reaction mixture showed approximately 50% conversion to the acidchloride after 1 hour, with complete conversion after stirring themixture overnight.

Procedure for the Synthesis of EMPOL 1008 Piperazine Amide

Into a 2 liter, four-necked round-bottom flask fitted with a Dean-Starktrap, reflux condenser, and mechanical stirrer were charged 1000 mltoluene, 152.3 grams piperazine, and 134.4 grams potassium carbonate.The mixture was refluxed for 30 minutes to dry the reactants. Thereaction mixture was then cooled to 10 degrees C. in an ice bath, and250 ml dichloromethane was added to aid stirring. The Empol 1008 acidchloride was added dropwise through an addition funnel at a ratesufficient to maintain a reactant temperature of 10-15 degrees C.Following the addition, the mixture was allowed to warm to ambienttemperature and stirred overnight. This material was then immediatelyconverted to the acrylamide.

Procedure for the Synthesis of EMPOL 1008 Piperazine Acrylamide

To the stirred reaction flask of the previous procedure was added 201.5grams potassium carbonate. The reaction mixture was cooled in an icebath to 12 degrees C., and 132.0 grams acryloyl chloride was addeddropwise over a period of 1 hour, maintaining a reactant temperature of8-10 degrees C. The reaction mixture was pressure filtered throughCelite to remove insoluble salts.

Procedure for Coating with EMPOL 1008 Piperazine Acrylamide

A coating formulation was prepared by mixing 93 parts by weight of theneat Empol 1008 piperazine acrylamide, and 7 parts by weight of aphotoinitiator blend consisting of 4 parts by weight of Darocure 1173, aphotoinitiator available from Ciba-Geigy, Hawthorne, N.Y., 2 parts byweight of Photomer 81, a liquid form of benzophenone available fromHenkel Corporation, Ambler, Pa., and 1 part by weight oftriethanolamine. This composition was coated at 6.86 micrometersthickness and cured in one pass at 100 ft./min. The resulting coatingexhibited a pencil hardness of 2H dissolved with four methyl ethylketone (MEK) rubs, zero adhesion by a rudimentary test (in simple peeltest with adhesive tape all of the coating in contact with the tapelifted from the substrate) and exhibited a Mandrel of less than 0.27.The resistance to MEK could be improved by the inclusion of adi-ethylenically unsaturated monomer, e.g. N,N'-bis-acrylamidopiperazine. A second coating at 76.2 micrometers thickness was cured inone pass at 100 ft./min. The resulting coating exhibited a pencilhardness of 2H dissolved with forty-five methyl ethyl ketone (MEK) rubs,and zero adhesion.

Example 3

A compound was prepared by the same (or substantially similar) procedureof Example 2, with the exception that dodecanedioic acid was employed toprepare a compound in accordance with scheme 3 wherein R⁸ is thedivalent alkylene radical having the formula --(CH₂)₁₀ --. A coatingformulation was prepared by mixing 93 parts by weight of thedodecanedioic acid piperazine acrylamide, and 7 parts by weight of aphotoinitiator blend consisting of 4 parts by weight of Darocure 1173, aphotoinitiator available from Ciba-Geigy, Hawthorne, N.Y., 2 parts byweight of Photomer 81, a liquid form of benzophenone available fromHenkel Corporation, Ambler, Pa, and 1 part by weight of triethanolamine.This composition was coated at 6.86 micrometers thickness and cured inone pass at 100 ft./min. The resulting coating exhibited a pencilhardness of 2H, dissolved after thirty-four methyl ethyl ketone (MEK)rubs, zero adhesion by a rudimentary test (in simple peel test withadhesive tape all of the coating in contact with the tape lifted fromthe substrate). A second coating at 76.2 micrometers thickness was curedin one pass at 100 ft./min. The resulting coating exhibited a pencilhardness of 2H dissolved only after greater than 100 methyl ethyl ketone(MEK) rubs, and zero adhesion. A third coating was prepared at 6.86micrometers thickness, but at 800 ft./min. The cured coating had apencil hardness of 5H and dissolved after six MEK rubs.

Example 4

A compound was prepared by the same (or substantially similar) procedureof Example 2, with the exception that adipic acid was employed toprepare a compound in accordance with scheme 3 wherein R⁸ is thedivalent alkylene radical having the formula --(CH₂)₄ --. A coatingformulation was prepared by mixing 93 parts by weight of the adipic acidpiperazine acrylamide, and 7 parts by weight of a photoinitiator blendconsisting of 4 parts by weight of Darocure 1173, a photoinitiatoravailable from Ciba-Geigy, Hawthorne, N.Y., 2 parts by weight ofPhotomer 81, a liquid form of benzophenone available from HenkelCorporation, Ambler, Pa, and 1 part by weight of triethanolamine. Thiscomposition was coated at 6.86 micrometers thickness and cured in onepass at 100 ft./min. The resulting coating exhibited a pencil hardnessof 2H and zero adhesion by a rudimentary test (in simple peel test withadhesive tape, all of the coating in contact with the tape lifted fromthe substrate) and exhibited a Mandrel of less than 0.27. A secondcoating at 76.2 micrometers thickness was cured in one pass at 100ft./min and exhibited a pencil hardness of 2H with 50% adhesion. A thirdcoating was prepared at 6.86 micrometers thickness, but at 800 ft./min.The cured coating had a pencil hardness of 2H.

Example 5

Coatings were prepared using N,N'-bis-acrylamido-piperazine as the onlypolymerizable monomer. A coating formulation was prepared by mixing 93parts by weight of the piperazine bis-acrylamide, and 7 parts by weightof a photoinitiator blend consisting of 4 parts by weight of Darocure1173, a photoinitiator available from Ciba-Geigy, Hawthorne, N.Y., 2parts by weight of Photomer 81, a liquid form of benzophenone availablefrom Henkel Corporation, Ambler, Pa, and 1 part by weight oftriethanolamine. This composition was coated at 6.86 micrometersthickness and cured in one pass at 100 ft./min. The resulting coatingexhibited a pencil hardness of 2H and zero adhesion by a rudimentarytest (in simple peel test with adhesive tape, all of the coating incontact with the tape lifted from the substrate) and exhibited a Mandrelof zero. A second coating at 76.2 micrometers thickness was cured in onepass at 100 ft./min and exhibited a pencil hardness of 2H with zeroadhesion.

Example 6

Alternate Procedure for the Synthesis of EMPOL 1008 Piperazine Amide

Into a flask fitted with a distillation head and mechanical stirrer werecharged 459.8 grams of Empol 1008 dimer acid, 12 ml of water and 4 dropsof an inert anti-foam (from Dow Chemical). To this mixture was added140.2 grams piperazine (a molar ratio of piperazine to dimer acid ofabout 2:1). The resulting mixture was heated to 126° C. over about 25minutes and then to about 160° C. over about 65 minutes and held atabout 160° C. for about 15 minutes. Then 4 drops of 85% phosphoric acidwas added and the mixture was held at about 160° C. for one hour. Afterone hour, 36 ml of water had distilled over. Infra-red analysis of themixture showed a residual carboxylate peak. The mixture was heated to175° C. and held over about 70 minutes after which the infra-redanalysis still showed a very small carboxylate peak. The mixture washeated to 200° C. and held over about 130 minutes after which theinfra-red analysis showed no remaining carboxylate.

Example 7

Synthesis of a Diester of Polybutyleneoxy glycol withN'-Acryloyl-N-(n-octenylsuccinoyl)-piperazine

A compound having the following formula was prepared: ##STR15## whereinR¹¹ is the residue of an alpha,omega-butyleneoxy glycol, R¹⁹ is theresidue of n-octenylsuccinic anhydride, n is 2 and R¹, R², and R³ areall hydrogen.

Into a 1 liter resin kettle fitted with mechanical stirrer and drynitrogen gas were charged 250.0 grams of a polybutyleneoxy glycol(available from Dow Chemical, Midland, Mich., as B100-1000 and having amolecular weight of about 1000 g/mole) 105.2 grams of n-octenylsuccinicanhydride, and 3.5 grams dimethylaminopyridine. The reaction mixture washeated to 100° C. until the anhydride was completely reacted asdetermined by infra-red analysis. The resulting diacid compound was thenreacted with piperazine as set forth in the alternate procedure for thesynthesis of EMPOL 1008 piperazine amide and the product was thenconverted to a diacrylamide compound by reaction with acryloyl chloride.

Example 8

The compound bis-(N'-acrylamido-piperazinyl) dimer acid amide wasprepared by the following reactions. The compound was then used to forma coating by the procedure set forth below.

Procedure for the Synthesis of EMPOL 1008 Piperazine Amide

Into a flask with a nitrogen atmosphere fitted with a distillation headand mechanical stirrer were charged 69.5 parts by weight of Empol 1008dimer acid, 21.1 parts by weight of piperazine (a molar ratio ofpiperazine to dimer acid of about 2:1), 2 parts by weight of water and0.13 parts by weight of an inert anti-foam (from Dow Chemical). To thismixture was added 0.15 parts by weight of 85% phosphoric acid. Theresulting mixture was heated to 160° C. and held at about 160° C. forabout 2 hours. Then 0.15 parts of additional 85% phosphoric acid wasadded and the mixture was heated to 180° C. and held at about 180° C.for two hours. The mixture was then heated to 200° C. and held at about200° C. for about 2 hours. The reaction is complete when the amine valueof the mixture is between 125-130 and the acid value is between 0-10.

Procedure for the Synthesis of EMPOL 1008 Piperazine Acrylamide

To the cooled product of the preceding reaction was added 151 parts byweight of a mixture of ethyl acetate and cyclohexane (in a weight ratioof 1: 1), 0.4 parts by weight of the methyl ether of hydroquinone, and25 parts by weight of triethylamine all under a dry nitrogen atmosphere.This mixture was cooled to 5° C. and 22.3 parts by weight of acryloylchloride (the distillate of a reaction product of 29.5 parts by weightof acrylic acid and 48.8 parts by weight of thionyl chloride in equalparts by weight of additional ethyl acetate/cyclohexane solvent to makea 1:1 solution of acryloyl chloride in solvent) was added at a rate thatmaintains the reaction temperature of 5-15° C. After addition iscomplete, the reaction mixture was allowed to warm to room temperature.The reaction is allowed to continue until the product shows noabsorption at 1800 cm⁻¹ by infra-red spectroscopy. The reaction mixturewas then mixed with 62 parts by weight of water to dissolve suspendedsolids and the resulting lower aqueous layer was separated by gravity.The organic layer was then heated to 55-60° C. at reduced pressure todistill solvent to less than 0.2% by weight of the product.

Procedure for Coating with EMPOL 1008 Piperazine Acrylamide

A coating formulation was prepared by mixing 93 parts by weight of theneat Empol 1008 piperazine acrylamide, and 7 parts by weight of aphotoinitiator blend consisting of 4 parts by weight of Darocure 1173, aphotoinitiator available from Ciba-Geigy, Hawthorne, N.Y., 2 parts byweight of Photomer 81, a liquid form of benzophenone available fromHenkel Corporation, Ambler, Pa, and 1 part by weight of triethanolamine.This composition was coated at 6.86 micrometers thickness and cured inone pass at 100 ft./min.

Example 9

The procedure of Example 8 can be repeated with the addition of 0.02parts by weight of N,N-dimethylaminopyridine to the 151 parts by weightof a mixture of ethyl acetate and cyclohexane.

Example 10

The procedure of Example 8 can be repeated with the addition of 0.2parts by weight of N,N-dimethylaminopyridine to the 151 parts by weightof a mixture of ethyl acetate and cyclohexane.

Example 11

The procedure of Example 8 can be repeated with the addition of 2.0parts by weight of N,N-dimethylaminopyridine to the 151 parts by weightof a mixture of ethyl acetate and cyclohexane.

What is claimed is:
 1. A composition having improved stability againstgelation comprising a compound of the formula: ##STR16## wherein: R¹,R², and R³ are each independently selected from the group consisting ofhydrogen and lower alkyl,B is a linking group selected from the groupconsisting of carbonyl, sulfonyl, amide, and carboxyl; n is one or zero;R⁴ is a radical selected from the group consisting of a higher aliphaticgroup, a substituted higher aliphatic group, an alicyclic group, aheterocyclic group, a non-benzenoid aromatic group, and a substitutedaromatic group, wherein viscosity of said composition does not increasemore than 20% when the composition is held at 60° C. for 150 hours.
 2. Acomposition of claim 1 wherein said R⁴ is selected from the groupconsisting of alkyl groups having from about 5 to about 50 carbon atoms,substituted alkyl groups having from about 5 to about 50 carbon atoms,cycloalkyl groups having from about 5 to about 50 carbon atoms, andsubstituted phenyl groups having from 7 to about 50 carbon atoms.
 3. Acomposition of claim 1 wherein n is one and B is a carbonyl group.
 4. Acomposition of claim 1 wherein n is one and B is a sulfonyl group.
 5. Acomposition of claim 1 wherein n is one and B is an amide group.
 6. Acomposition of claim 1 wherein n is one and B is a carboxyl group.
 7. Acomposition of claim 1 wherein n is zero.
 8. A composition of claim 7wherein R⁴ has from 7 to about 50 carbon atoms.
 9. A composition ofclaim 1 wherein R⁴ has the formula --R⁸ --(B')_(m) --R, wherein R⁸ is adivalent group selected from the group consisting of a higher alkylenegroup, a substituted higher alkylene group, an aromatic group, and asubstituted aromatic group, B' is a linking group selected from thegroup consisting of carbonyl, sulfonyl, amide, and carboxyl, m is zeroor one, and R is selected from the group consisting of an aliphaticgroup, a substituted aliphatic group, an alicyclic group, a heterocyclicgroup, an aromatic group, and a substituted aromatic group.
 10. Acomposition of claim 1 wherein R⁴ has at least seven carbons and isethylenically unsaturated.
 11. A composition of claim 1 wherein R⁴ isselected such that the compound has the formula: ##STR17## wherein eachR¹, R², and R³ is independently selected from the group consisting ofhydrogen and lower alkyl,each B and B' linking group is independentlyselected from the group consisting of carbonyl, sulfonyl, amide, andcarboxyl; n and m are independently one or zero; R⁸ is a divalentradical selected from the group consisting of an aliphatic group, analicyclic group, an aromatic group, and a heterocyclic group.
 12. Acomposition of claim 11 wherein R⁸ has from 5 to about 50 carbon atomsand is selected from the group consisting of a higher alkylene group, asubstituted higher alkylene group, an aryl group, an aralkyl group, andan alkaryl group.
 13. A composition of claim 1 wherein R⁴ has theformula: ##STR18## wherein R⁸ is a divalent group selected from thegroup consisting of a higher alkylene group, a substituted higheralkylene group, an aromatic group, and a substituted aromatic group, andR¹², R¹³, and R¹⁴ are independently selected from the group consistingof hydrogen and lower alkyl.
 14. A composition of claim 13 wherein R¹²,R¹³, and R¹⁴ are hydrogen and R⁸ is an alkylene radical selected fromthe group consisting of unsubstituted, straight chain alkylene radicalsand alkylene radicals derived from dimer acids.
 15. A composition ofclaim 1 wherein R⁴ is an alkylene-amido group having the structure --R⁸--C(O)--N(R⁹)--R¹⁰, wherein R⁸ is a divalent group selected from thegroup consisting of a higher alkylene group, a substituted higheralkylene group, an aromatic group, and a substituted aromatic group, andR⁹ and R¹⁰ are independently selected from the group consisting of analiphatic group, an alicyclic group, an aromatic group, and aheterocyclic group, provided that R⁹ and R¹⁰ may together form adivalent alicyclic or heterocyclic radical.
 16. A composition of claim15 wherein R⁹ and R¹⁰ are selected from the group consisting of an alkylgroup, a substituted alkyl group, an alkenyl group, a substitutedalkenyl group, an aromatic group, and a substituted aromatic group. 17.A composition of claim 15 wherein R⁹ and R¹⁰ together form a divalentalicyclic or heterocyclic radical.
 18. A composition of claim 15 whereinR⁸ is an alkylene radical selected from the group consisting ofunsubstituted, straight chain alkylene radicals and alkylene radicalsderived from dimer acids.
 19. A composition of claim 1 wherein R⁴ is analkylene-ester group having the structure --R⁸ --C(O)--O--R¹¹, whereinR⁸ is a divalent group selected from the group consisting of a higheralkylene group, a substituted higher alkylene group, an aromatic group,and a substituted aromatic group and R¹¹ is selected from the groupconsisting of aliphatic group, an alicyclic group, an aromatic group,and a heterocyclic group.
 20. A composition of claim 19 wherein R⁸ is analkylene radical selected from the group consisting of unsubstituted,straight chain alkylene radicals and alkylene radicals derived fromdimer acids and R¹¹ is an alkyl group.
 21. A composition of claim 19wherein R⁸ is an aromatic group or a substituted aromatic group and R¹¹is an alkyl group.
 22. A composition of claim 21 wherein R⁸ is a phenylgroup and R¹¹ is an n-butyl group.
 23. A polymerizable compositioncomprising a composition of claim 1 in an amount sufficient tomeasurably affect a macro-observable physical property of a polymerprepared therefrom, as compared to said polymer prepared without saidamount of said polymerizable compound.
 24. A polymerizable compositionof claim 23 wherein said compound is present in a major amount on a molepercent basis of all of the polymerizable compounds of said composition.25. A polymerizable composition of claim 23 further comprising aphotoinitiator susceptible to ultra-violet radiation.
 26. Apolymerizable composition of claim 23 wherein said composition isessentially free of acrylate monomers.
 27. A process for a stabilizing acomposition comprised of a compound of the formula: ##STR19## wherein;R¹, R², and R³ are each independently selected from the group consistingof hydrogen and lower alkyl,B is a linking group selected from the groupconsisting of carbonyl, sulfonyl, amide, and carboxyl; n is one or zero;R⁴ is a radical selected from the group consisting of a higher aliphaticgroup, a substituted higher aliphatic group, an alicyclic group, aheterocyclic group, a non-benzenoid aromatic group, said processcomprising reducing the amount of unreacted piperazine in thecomposition to a level that viscosity of the composition does notincrease more than 20% when the composition is held at 60° C. for 150hours when said composition is mixed with a polymerization inhibitor.28. The composition of claim 1 wherein the viscosity of the compositiondoes not substantially increase when the composition is held at 60° C.for 150 hours.
 29. The composition of claim 11 wherein the compound isbis(N'-acrylamido-piperazinyl) dimer acid amide.
 30. The composition ofclaim 11 wherein the compound is bis(N'-acrylamido-piperazinyl)dodecanedioc acid amide.
 31. The composition of claim 11 wherein thecompound is bis(N'acrylamido piperazinyl) adipic acid amide.
 32. Acomposition having improved stability against gelation comprising acompound of the formula; ##STR20## wherein: R¹, R², and R³ are eachindependently selected from the group consisting of hydrogen and loweralkyl,B is a linking group selected from the group consisting ofcarbonyl, sulfonyl, amide, and carboxyl; n is one or zero; R⁴ is aradical selected from the group consisting of a higher aliphatic group,a substituted higher aliphatic group, an alicyclic group, a heterocyclicgroup, a non-benzenoid aromatic group, and a substituted aromatic group,wherein viscosity of said composition goes not increase more than 100%when the composition is held at 60° C. for 3 hours.
 33. The compositionof claim 32 wherein the viscosity does not increase more than 100% whenthe composition is held at 60° C. for more than 150 hours.
 34. A methodas claimed in claim 27 wherein said polymerization inhibitor is selectedfrom the group consisting of quinones and phenothiazine.
 35. A method asclaimed in claim 34 wherein said polymerization inhibitor isphenothiazine.
 36. The composition of claim 32 wherein the viscosity ofsaid composition does not increase more than 50* when the composition isheld at 60° C. for 150 hours.
 37. The composition of claim 32 whereinthe viscosity of said composition does not increase more than 50* whenthe composition is held at 60° C. for 3 hours.
 38. The composition ofclaim 32 wherein the viscosity of said composition does not increasemore than 20% when the composition is held at 60° C. for 3 hours.